Scientists Engineer Stem Cells to Fight HIV

December 9, 2009

Scientists Engineer Stem Cells to Fight HIV

The approach might provide a way to prime the immune system against a variety of diseases.

Stem cells
genetically engineered to carry a molecule (derived from an HIV-infected person)
that recognizes the virus could provide a new way to bolster the immune system
against the disease, according to new research published this week in PLoS ONE. When
implanted into mice, the stem cells developed into mature immune cells that
could target cells with HIV specific proteins. Researchers are using a similar
approach to prime the human immune system against cancer.

“We
have demonstrated in this proof-of-principle study that this type of approach
can be used to engineer the human immune system, particularly the T-cell
response, to specifically target HIV-infected cells,” says lead
investigator Scott G. Kitchen, an assistant professor of medicine in the
division of hematology and oncology at the David Geffen School of Medicine at
UCLA and a member of the UCLA AIDS Institute, in a press release.
“These studies lay the foundation for further therapeutic development that
involves restoring damaged or defective immune responses toward a variety of
viruses that cause chronic disease, or even different types of tumors.”

According to the release:

Taking CD8 cytotoxic T lymphocytes–the “killer” T cells that
help fight infection–from an HIV-infected individual, the researchers
identified the molecule known as the T-cell receptor, which guides the T cell
in recognizing and killing HIV-infected cells. These cells, while able to
destroy HIV-infected cells, do not exist in enough quantities to clear the
virus from the body. So the researchers cloned the receptor and genetically
engineered human blood stem cells, then placed the stem cells into human thymus
tissue that had been implanted in mice, allowing them to study the reaction in
a living organism.

The engineered stem cells developed into a large population of mature,
multifunctional HIV-specific CD8 cells that could specifically target cells
containing HIV proteins. The researchers also found that HIV-specific T-cell
receptors have to be matched to an individual in much the same way that an
organ is matched to a transplant patient.

Researchers hope the technology will have broader applications.”This
approach could be used to combat a variety of chronic viral diseases,” says co-author Jerome A. Zack, a UCLA professor of medicine in the division of hematology
and oncology and associate director of the UCLA AIDS Institute, in the same release.
“It’s like a genetic vaccine.”